1. Field of the Invention
This invention applies generally to data input keyboards, and more particularly to any character data input keyboard which purpose is to enable two-handed operation on a plurality of keys, clustered and ordered so that operation is possible without the aid of continuous operator vision directed at the keyboard. The present invention is a keyboard arrangement especially suited for facile, rapid entry of character data. It is an arrangement of keys comprising a central matrix of keys located between divided clusters of keys, the central matrix readily accessable by medial movement of the index fingers and thumbs from resting positions in the divided clusters. The central matrix of keys has columns of four or more keys and may include numeric keys and/or keys of numeric operators, punctuation and screen editing at a video display terminal.
2. Ergonomic considerations
Medical theory, presented in HUMAN NEUROANATOMY (sixth edition) by R. C. Truex and M. B. Carpenter, suggests that the human brain evolved from less specialized forms which in the earliest stages were characterized by a cephalic enlargement of a single neural tube. This singularity at the top eventually gave way to a bifurcation of neuroanatomy which has resulted in functionally distinct right and left hemispheres of cerebral and cerebellar cortex.
Two distinct systems of neural control mediate motor (muscular) function. The more primitive system, called the extrapyramidal system, is functional in all vertebrates of the phylogenetic tree. In the human is the highest development of the pyramidal system, which functions in superposition to the more primitive but still importantly existent extrapyramidal system, the latter mediating basic reflexes and gross movements. Skilled volitional movements originate in giant pyramidal cells of Betz in the so called motor area (Brodmann's area 4) on the contralateral side of the cerebral cortex, and are conditioned by impulses from contralateral and ipselateral cerebellum.
Decisions which initiate fine motions in the hand, such as keystrokes on a character data input keyboard, must be followed by assignment to either the right or left precentral cortical area of the brain for effecting a decision. From there impulses are relayed, via corticofugal fibers of the pyramidal motor system, to the neuromuscular junctions in the contralateral hand that effect an appropriate keystroke, the elemental quantum of keyboard activity.
Because of this structural, binary separation of pyramidal neuromuscular function, decisions precedent to such function could be expedited by more clearly distinguishing, in the field of sensory input to the brain, the operative domain for the digits of each hand. This is the basis for one important feature of the present invention: that the keyboard be divided into clearly defined left and right keyboard areas, such that the human operator, with sternum aligned in the vertical plane bisecting the line connecting the epicenters of the divided cluster of keys, may symmetrically access keys located in the partition dividing the separated clusters.
As a result of greater use of the medial two digits--thumb and index finger--in the course of living, these are stronger than the lateral digits, namely: middle finger, ring finger, and little finger. Within the precentral motor area of the human cerebral cortex, a greater number of pyramidal neuro-effector cells are devoted to control of the thumb than exist for control of any of the fingers. In this regard the thumb is the most "intelligent" of the hand's digits.
The index finger, stronger than any of the other fingers, and the little finger are equal in the amount of neural representation in the motor areas. Neural control, mobility, and endurance are three parameters applicable to the function of character data entry. The middle finger and ring finger are least capable in light of these parameters, and each serve the minimum 4 keys on the conventional alphanumeric keyboard depicted in FIG. 1, the basis for which is commonly called the "Sholes cluster", or "QWERTY cluster". In usual practice, the index finger serves 8 keys, the little finger serves as many as 12 keys, while both thumbs serve only one key.
It is apparent that conventional, two-hand, alphanumeric keyboard entry underutilizes the index fingers and thumbs. Furthermore, as need increases for larger character sets and function keys, additional keys are placed lateral to the basic Sholes cluster. The result is that the little finger is overutilized and commonly pulls the hand away from the "Home" position on the keyboard when accessing one of the more lateral keys.
For numeric entry, three arrangements of ten keys are common:
(1) 1 row of 10 numbers in 10 columns: [1.times.10]
(2) 3 rows of 9 numbers in 3 columns and a tenth key adjacent: [3.times.3+1]
(3) 5 rows of 10 keys in 2 columns: [5.times.2].
Other variations, such as [2.times.5], [4.times.2+2], [10.times.1], etc. have not commonly been applied to the ordering of keys on a numeric keypad. In general, the third numeric arrangement listed above allows for a binary separation of keys, aligned with the division of the human cortex which effects operation on the keys.
Early in man's evolution arose the capacity to point, coupled with use of the index finger. As it is the index finger which naturally is used by the human to point in space, so is it proper to consider this human capacity in conjunction with direction of cursor movement at the video display control keyboard.
It is also well established that the index finger is favored by the human when a keyboard is accessed by only one digit. Consequently, a cluster of keys accessible to one-digit operation by the index finger, if centered, can be accessed equally well by right-handers and left-handers.
Since the majority of keyboard operators are right-handed, meaning that the left cerebral cortex is "dominant", a variation of the present invention makes use of the differential specialization of function that applies to the bipolarity of human neuro-cortical function. The left cortical hemisphere is more active in language and numeric processes while the right cortical hemisphere is more active in spatial relations. Specific application of this concept will be discussed hereinafter.
3. Description of the Prior Art
U.S. Pat. No. 207,559 (issued Aug. 27, 1878) to C. L. Sholes is widely credited as the forebearer of the existing conventional alphanumeric keyboard arrangement. Within the 50 year period in which Sholes created and, in conjunction with Remington, established this standard, many other alternatives were proffered from both sides of the Atlantic. In 1864, Mitterhofer in Austria and Pratta in Britian obtained patents for typewriters with keyboards that were split into right and left keyboard areas, such that the operative domain for each hand was demarcated by a middle region of no keys in the case of the latter and nonalphanumeric keys in the former.
In light of the standardization of the alphanumeric keyboard, proposed alterations throughout the past century have met with little commercial success. For example, several patents have proffered a supposed more optimal arrangement of the alphanumeric keyboard. Dvorak, in U.S. Pat. No. 2,040,248 (1937), focused on a single cluster arrangement of the letter keys while not challenging the [1.times.10] arrangement of the numeric keys.
U.S. Pat. No. 3,225,883 refers to a nonconventional alphanumeric keyboard in which a central cluster of 6 numeric keys, arranged in two columns of three keys, serve entry of the 10 numbers. In this patent, several letter keys also occupy the horizontally central keyboard region.
Austrian Pat. No. 238736 depicts a nonconventional keyboard in which a [5.times.2] numeric keypad is installed, off-center, in the medial area of a divided keyboard comprising 6 rows of alphanumeric and accessory keys. There is no spacebar in the bottom row. The numeric keypad shares the middle region of the keyboard with a set of sundry keys for puncuation, umlauted letters, and other keytypes, not so ordered as to be readily applicable to the conventional keyboard arrangement. The positioning, in this invention, of the numeric keys in an alphanumeric cluster is similar to the positioning of the number keys in a keyboard manufactured by MICRO SWITCH, as shown in Electronic Design 23:09 p55, 1972. Numeric entry there may require simultaneous depression of a Shift key, illustrating an embedded numeric keypad.
U.S. Pat. No. 3,305,062 (issued Feb. 21, 1967) to E. D. Kittredge, shows two separate fields of 25 keys, each a mirror image of the other. The middle region is not utilized.
U.S. Pat. No. 3,558,820 demonstrates centering of number keys in the middle region of a non-divided, unconventional keyboard. However, the numeric keypad comprises two redundant sets of 10 numbers in [4.times.5] configuration having no familiar intra-columnar ordering of keys. Sharing the middle region of the keyboard is a set of punctuation keys placed beneath the numeric keypad.
U.S. Pat. No. 3,698,532 shows a separation of a non-Sholes alphanumeric keyboard, retaining the [1.times.10] arrangement of the number keys.
U.S. Pat. No. 3,825,101 involves the location of a [3.times.3+1] numeric keypad in a plane several inches above the plane of a conventional alphanumeric keyboard.
U.S. Pat. No. 3,945,482 utilizes separation of the alphanumeric keyboard so as to better utilize the medial digits. The conventional [1.times.10] numeric arrangement is retained. The index fingers each access 2 more keys while each thumb serves 3 more keys than in the conventional keyboard arrangement.
Commensurate with the development of computer-related alphanumeric keyboards arose the design concept of supplementing the conventional typewriter keyboard with an auxilliary, calculator-type keypad. The [5.times.2] and [3.times.3+1] are two common means of arranging ten numbers in this application.
U.S. Pat. No. Des. 249,513 demonstrates the [5.times.2] arrangement while the [3.times.3+1] arrangement is evident in U.S. Pat. No. Des. 261,273. In both cases, the calculator-type numeric entry keypad is located laterally and removed from the conventional alphanumeric keyboard cluster. U.S. Pat. No. Des. 250,022 pictures an arrangement of keys incorporating all three instances of common numeric keypad arrangements. A [5.times.2] numeric keypad is located on the left side of and separate from the five-row cluster of the conventional alphanumeric keyboard. It may serve as ten function keys, requiring single-digit entry of the left hand, in lateral excursion from the conventional cluster. On the right of the conventional cluster is a [3.times.3+1] numeric entry keypad, readily accessed by the right index finger in lateral excursion from its Home position in the conventional cluster. In the top row of this keyboard is the conventional [1.times.10] array of number keys.
U.K. Pat. No. 2,041,295 demonstrates a separation of the alphanumeric cluster into right-hand and left-hand clusters, in the form of U.S. Pat. No. 3,698,532. In this patent, 4 rows comprise the alphanumeric cluster that includes the top row [1.times.10] numeric arrangement. Here the middle is augmented by four additional keys in a [2.times.2] array served equally by the thumbs and index fingers.
More recently, the Maltron keyboard arrangement, U.S. Pat. No. 4,244,659, is of the form of Einbinder's U.S. Pat. No. 3,945,482, discussed above, providing separation of the alphanumeric cluster and ten keys centered in the keyboard, though not in a regular array, and all accessed by the thumbs.
U.S. Pat. No. Des. 250,022 is currently implemented approximately in the IBM Personal Computer keyboard. As is commonly found in video display computer terminal keyboards, clusters of keys for special function are located lateral to the conventional alphanumeric cluster. For example, the keyboard for certain microcomputers is expanded to greater horizontal dimensions in accomodating separate clusters of keys for special function, calculator type numeric entry, cursor control, and other editing functions.
In the IBM PC keyboard, two of these functions--cursor control and calculator-type numeric entry--are combined in a single keypad requiring the toggling of an additional key for selecting one of the two functions. Most significant is the use of 30 numeric designated keys to serve three types of functions that, in the present invention requires only 10 keys.